Anatomy and morphology

The Philippine Tarsier is a tiny animal, measuring about 85 to 160 millimetres (3.35 to 6.30 in) in height makes this one of the smallest primates. The small size makes it difficult to spot. The mass for males is between 80 and 160 grams, usually lighter for females, somewhat heavier than other Tarsius such as the Pygmy tarsier.[7] The average adult is about the size of a human fist and will fit very comfortably in the human hand (see image below).

Like all tarsiers, the Philippine Tarsier's eyes are fixed in its skull; they cannot turn in their sockets. Instead, a special adaptation in the neck allows its round head to be rotated 180 degrees. The large membranous ears are mobile,[8] appearing to be almost constantly moving, allowing the tarsier to hear any movement. It has uniquely large eyes (disproportionate to its head and body), which are listed in the Guinness Book of Records as the largest eyes on any mammal. These huge eyes provide this nocturnal animal with excellent night vision.[9]

The Philippine Tarsier has skinny and rough fur which is colored gray to dark brown. The thin tail, usually used for balance, is naked or bald except for a tuft of hair at the end, and is about twice the body length. Its elongated "tarsus," or ankle bone, which gives the tarsier its name, allows it to jump at least three meters from tree to tree without having to touch the ground.[9] Its long digits are tipped with rounded pads that allow T. syrichta to cling easily to trees and to grip almost any surface. The thumb is not truly opposable, but the first toe is. All of the digits have flattened nails, except for the second and third toes, which have sharp claws specialized for grooming.[10]

The dental formula is 2:1:3:3 in the upper jaw and 1:1:3:3 in the lower jaw, with relatively small upper canines.[8]

Angry Philippine Tarsier, showing lower jaw dentition

Range and distribution

The Philippine Tarsier, as its name suggests, is endemic to the Philippine archipelago.[11]Tarsius syrichta populations are generally found in the southeastern part of the archipelago. Established populations are present particularly on the islands of Bohol, Samar, Leyte and Mindanao.[3] They have also been found on various isolated islands within its known range, such as Maripipi Island, Siargao Island, Basilan Island and Dinagat Island.[2]

Ecology and life history

Tarsier tree climbing

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Habitat

The Philippine Tarsier's habitat is the second growth, secondary forest, and primary forest from sea level to 700 m.[11] Its habitat also includes tropical rainforest with dense vegetation and trees that offer it protection like tall grasses, bushes and bamboo shoots.

Research findings also show that the Philippine Tarsier prefer dense, low-level vegetation in secondary forests, with perching sites averaging 2 meters above the ground.[12]

Home range

Initial studies show that the Philippine Tarsier appears to have a home range of 1 to 2 hectares.[3] Recent research shows that home ranges averaged 6.45 hectares for males and 2.45 hectares for females (MCP and Kernel 95%), allowing for a density of 16 male and 41 female tarsiers per 100 ha.[13]

Research findings also show that while both male and female tarsiers are solitary animals, they cross each other's paths under the cover of nightfall as they hunt for prey. They travel up to one and a half kilometres across the forest and the optimal area is more than six hectares.[5]

Ecosystem roles

Besides human hunters, feral cats banished from nearby communities are the species' main predators, though some large birds are known to prey on it as well.[14] Because of its nocturnal and arboreal habits, the Philippine Tarsier is most likely to fall prey to owls, or to small carnivores which it can encounter in its canopy homes.

Feeding ecology

The Philippine Tarsier is carnivorous. Primarily insectivorous, its diet consists of live insects and it has also been observed to feed on spiders, small crustaceans, and small vertebrates such as small lizards and birds. Tarsius syrichta preys on live insects, particularly crickets and grasshoppers. Upon seizing its prey, the tarsier carries it to its mouth using both hands.[3]

Behavior

The Philippine Tarsier is a shy nocturnal[3] animal that leads a mostly hidden life, asleep during the day and only active to look for food during the night. During the day, it sleeps in dark hollows close to the ground, near the trunks of trees and shrubs deep in the impenetrable bushes and forests. They only become active at night, and even then, with their much better sight and amazing ability to maneuver around trees, are very well able to avoid humans.[6]

It is arboreal[3] and is a vertical clinger and leaper,[8] habitually clinging vertically to trees and are capable of leaping from branch to branch.

Communication

The Philippine Tarsier uses varied means of communication. Although less vocal than many primate species, it uses calls which are often associated with territorial maintenance and male-female spacing.[3] Its "loud call" is a loud piercing single note. When content, it emits a sound similar to a soft sweet bird-like twill. And when several tarsiers come together, they have a chirping, locust-like sound.[15]

Its vocal communication is the distress call made by infants when they are separated from their mothers. It is also the call made by males to their mates during mating season. Its olfactory communication is the marking of a scent from the circumoral gland which the female uses to mark her mate with the gland located around the mouth. It is also the marking of a male's territory with the use of urine. Its tactile communication is the social grooming done when one tarsier grooms the other, removing dead skin and parasites, observed in females on adult males, as well as in females on their offspring.[8]

Life history

Tarsier with a baby

Reproduction

The Philippine Tarsier's pregnancy or gestation period lasts about 6 months. The female's estrous cycle lasts 25–28 days.[8] Mating season begins in April to May. The males deposit a mating plug in the female's vagina after intercourse. The female gives birth to one offspring per gestation. The infant is born with a lot of hair and born with its eyes open. The females carry their infants in their mouth. A new born can already cling to branches and in less than a month after birth, it can start leaping.

Etymology and taxonomic history

The Philippine Tarsier has been called "the world's smallest monkey" or "smallest primate" by locals before. It is related to other primates, including monkeys, lemurs, gorillas and humans but it occupies a small evolutionary branch between the strepsirrhineprosimians, and the haplorrhinesimians. While it is a prosimian, and used to be grouped with the rest of the prosimians, it has some phylogenetic features that caused scientists to classify it as a haplorrhine and, therefore, more closely related to apes and monkeys than to the other prosimians.

The smallest primate is the Madame Berthe's Mouse Lemur (Microcebus berthae)[17], at around one third the weight this species.[18] The superlative 'smallest monkey' often refers to the Pygmy Marmoset (Cebuella pygmaea), an animal with a larger body size. The Philippine Tarsier is considered to be the mammal with the biggest eyes, 16 mm across, in proportion to its body size.[19] The Philippine Tarsier was only introduced to Western biologists in the 18th century through the description given to J. Petiver by the missionary J.G. Camel of an animal said to have come from the Philippines. Petiver published Camel's description in 1705 and named the animal Cercopithecus luzonis minimus which was the basis for Linnaeus' (1758) Simia syrichta and eventually Tarsius syrichta, the scientific name it is known at present.[20] Among the locals, the tarsier is known as "mamag", "mago", "magau", "maomag", "malmag" and "magatilok-iok".[21]

According to records of the Philippine Tarsier Foundation, three subspecies are presently recognized: Tarsius syrichta syrichta from Leyte and Samar, Tarsius syrichta fraterculus from Bohol and Tarsius syrichta carbonarius from Mindanao.[22] The IUCN taxonomic notes lists two subspecies but that the non-nominate one is poorly defined as present, so the species is treated as a whole. Tarsius syrichta carbonarius and Tarsius s. fraterculus: Hill (1955) recognized these taxa as weakly defined subspecies. Niemitz (1984) found the differences to be insignificant based upon comparisons with museum specimens. Musser and Dagosto (1987) felt that the available museum specimens were insufficient to resolve the issue, but mentioned that Heaney felt that a single male tarsier from Dinagat might be distinct. Groves (2001) did not recognize any subspecies of T. syrichta.[23]

Importance to humans

A Philippine Tarsier standing on a human arm.

There is no known negative impact of the Philippine Tarsier on humans, just as long as it is in its native environment. However, when kept as pets, there is a possibility that the species may spread worms and other parasites to their human owners.

Tarsiers used to be kept as pets or sold for trade, although their survival in captivity is erratic due to their need for live insects upon which to feed. Scientists are interested in these animals because of their unique taxonomic position, and study of tarsiers may aid human economies.

Conservation

In 1986, the Philippines Tarsier was assessed as Endangered by the IUCN Conservation Monitoring Centre 1986. It was still assessed as Endangered by the IUCN Conservation Monitoring Centre in 1988, as well as in 1990 (IUCN 1990). In 1996, it was assessed as Lower Risk/conservation dependent by Baillie and Groombridge (1996).[24]

On September 13, 1991, the Department of Environment and Natural Resources (DENR), per DENR Administrative Order Number 48 or DAO 48, listed the Philippine Tarsier as an endangered species: species and subspecies of wildlife whose populations are in danger of extinction and whose survival is unlikely if the causal factors continue operating.[25]

The Philippine Tarsier is listed in Appendix II of CITES,[26] and the U.S. ESA classifies it as threatened.[27]

In 2000, the IUCN, having continuously listed the Philippine Tarsier as endangered,[1] further assessed the Tarsius syrichta in its red list category and criteria as Data Deficient (DD)[2] which means that there is inadequate information to make a direct or indirect assessment of its risks of extinction based on its distribution and/or population status. Further, it basically means that it is not known how close the species is to extinction or if it is a lower risk.

Being classified as such, the sale and trade of the species is prohibited. In addition, research on the species, particularly those using invasive techniques, is controlled by the DENR Environment Management Bureau (DENR-EMB) and requires Environmental Compliance Certificate/Environmental Impact Statement or ECC/EIS.

Threats to the species

For the past 45 million years, tarsiers have inhabited rainforests around the world, but now they only exist on a few islands in the Philippines, Borneo and Indonesia.[5] In Bohol, the Philippine Tarsier was a common sight in the southern part of the island until the 1960s. Since then, the number has dwindled to as few as an estimated 1000 still left in the wild.[citation needed] Once protected by the humid rainforests and mist-shrouded hills, these mysterious primates struggle to survive as their home is cleared for crop growing.

Due to the quickly growing human population, which causes more and more forests to be converted to farmland, housing areas and roads, the place where the Philippine Tarsier can live its secluded life is disappearing.[6]

Along this line, the dwindling of Philippine forests has posed a grave and significant threat to the survival of the Philippine Tarsier because this results in the destruction of its natural forest habitat. Indiscriminate and illegal logging, cutting of trees for firewood, "kaingin" or slash and burn method of agriculture, urbanization patterns have encroached on the habitats of the tarsier, causing the tarsier to be threatened or endangered.[28]

The unabated hunting of the species by humans for house pets or for trade has contributed to its decline as well. Hunting tarsiers to sell as pets was a thriving industry until recently. Because of its adorable and benign appearance, many have been lured to keep the Philippine Tarsier as pets. This demand fuels the capture and illegal trade of the animal further diminishing its remaining number.[citation needed] Moreover, the life span for wild tarsiers is 24 years, but often as little as 12 years in captivity. Aside from the issues of replicating a natural diet, climate, and exercise that may reduce a captive tarsier's lifespan, stress may be added by the fact that many human owners want to interact with and display their pets by day, interrupting their nocturnal lifestyle.[citation needed]

Paradoxically, indigenous superstition coupled with relatively thick rainforest, particularly in Sarangani province, have apparently preserved this endangered species. Indigenous tribes leave the Philippine Tarsiers in the wild because they fear that these animals could bring bad luck. One belief passed down from ancient times is that they are pets belonging to spirits dwelling in giant fig trees, known as belete trees. If someone harms a tarsier they need to apologize to the spirits of the forest, or it is thought they will encounter sickness or hardship in life.[5]

Conservation efforts

Legislation

Signage at entry to Philippine Tarsier Foundation Research and Development Center

Several legislations have been passed to protect and conserve the Philippine Tarsier. DENR Administrative Order No. 38, Series of 1991 (DAO No. 38) included the Philippine Tarsier among the national protected wildlife species and proposed its listing under Appendix 1 of the Convention on International Trade in Endangered Species (CITES). More over, the IUCN/SSC Primate Specialist Group had given the species Conservation Priority Rating 4, which means that the species is highly vulnerable and threatened by habitat destruction and/or hunting.

Proclamation 1030 was signed by then President of the PhilippinesFidel V. Ramos on June 23, 1997, declaring the Philippine Tarsier a specially protected faunalspecies. [1] The Proclamation contains that since the Philippine Tarsier, endemic to the Philippines, offers immense ecological, aesthetic, educational, historical, recreational and scientific value to the country and to the Filipino people, it is a matter of national concern since it forms part of the Philippine heritage. The Proclamation thus prohibits the hunting, killing, wounding, taking away, or possession of the Philippine Tarsier, but that possession for educational, scientific, conservation-centered research purposes may be allowed upon certification of the Department of Environment and Natural Resources (DENR) Secretary. Further, the DENR is also tasked to collaborate with other concerned government agencies, NGOs, local government units and local communities in the conduct of accelerated and expanded field researches and to avail of financial support and technical cooperation from local and international entities, as may be deemed necessary to implement the provisions of the Proclamation.[29]

Republic Act No. 7586, otherwise known as the National Integrated Protected Areas System (NIPAS) Act of 1991 mandates the establishment of appropriate sanctuaries to preserve and protect the Philippine Tarsier.

There are also legislations at the other local level, including Provincial ordinances and proclamations (Bohol Province), Municipal Ordinances (Corella), Barangay Ordinances (Canapnapan, etc.).

On July 30, 2001, Philippine President Gloria Macapagal-Arroyo signed Republic Act No. 9147 otherwise known as the Wildlife Resources Conservation and Protection Act that provided for the conservation and protection of wildlife resources and their habitats, including the Philippine Tarsier, and its inclusion as a flagship species.[30]

Conservation initiatives

Conserving biological diversity involves tools like the protection of natural or semi-natural ecosystems, the restoration and rehabilitation of degraded lands, and ex-situ conservation techniques.[31]In-situ conservation is the maintenance of plant and animal genetic material in their natural habitat. The aim of in-situ conservation is to allow the population to maintain itself within the community of which it forms part and in the environment to which it is adapted so that it has the potential for continued evolution.[31]Protected areas are among the most valuable in situ conservation tool and cost-effective means for preserving genes, species, and habitats and for maintaining various ecological processes of importance to humanity. They are set aside to conserve species that cannot be preserved ex-situ and wild crop relatives. The protected areas system maintain species diversity by protecting the range of different community types and by allowing for changes in species' distributions. They do this by protecting the diversity of physical environments containing a range of situations to allow organisms to adjust their local distribution in response to climate change and linking corridors of natural and modified environments, which will allow species to change their continental distributions.[31]

Reforestation attempts to restore deforested areas using indigenous tree species are more consistent with biodiversity conservation strategies such as protected area management and natural regeneration. This allows for enhanced forest ecological services such as watershed functions, wildlife habitat, and maintenance. As a result, local biodiversity is protected and rehabilitated. In trial sites in Leyte, local fauna has been seen to quickly re-colonize the mixed plantations of rainforestation cooperators/farmers. Birds and fruit bats initially, and then larger mammals including Philippine Tarsier (Tarsius syrichta) and Flying Lemur (Cynocephahis volans) were seen in the sites after four years (Goltenhoth et al. 2000).[32]

Philippine debt-for-nature swap program

To save the Philippine Tarsier from extinction, the Philippine government has launched various initiatives. Efforts to conserve the species started in 1988 when a study on the tarsier habitat requirements was initiated in Corella, Bohol by the Parks and Wildlife Bureau or PAWB under the financial grant of the Wildlife Conservation International. This was followed by a Philippine Tarsier Project by Department of Environment and Natural Resources Region 7 in 1991-1992 under the Debt-for-Nature Swap Project.[33]

The debt-for-nature swap, first proposed by the World Wildlife Fund for Nature in 1984, is a scheme in which conservation organizations acquired title to debt, either by direct donation from a bank, or by raising the cash to buy it, and then negotiate with the debtor countries to obtain debt repayment in local currency at a favorable conversion rate, or to secure conservation measures/activities.[33]

Haribon Foundation was identified as the local NGO partner in its venture. As the local NGO partner, Haribon Foundation became the fund manager of the program, thus, all financial transactions with the Central Bank of the Philippines and the World WWF were handled while release of funds to all the projects was facilitated. One of the projects implemented on the first year was the "Endangered Species Conservation: Philippine Tarsier" supervised by the Department of Environment and Natural Resources or DENR.[34]

Philippine Tarsier Foundation Incorporated

The Philippine Tarsier Foundation Inc. based in Tagbilaran City, Bohol, Philippines, is spearheading the campaign to preserve the Philippine Tarsier. Under a Memorandum of Agreement with the DENR signed on April 27, 1997, its mission is: to establish a forest reserve on the island of Bohol which shall serve as the sanctuary of the Philippine Tarsier; to protect and manage the tarsier sanctuary through the active participation of local communities; to establish and maintain a wildlife research laboratory for the study of the ecology and biology of the Philippine Tarsier; to establish and maintain visitor facilities for ecotourism and disseminate information material about the Philippine Tarsier with emphasis on the species' protection and conservation."[35]

To date, the Philippine Tarsier Foundation has acquired 7.4 hectares of land in Corella, Bohol for the sanctuary. With the DENR playing an oversight role, the foundation has asked other Bohol towns with Philippines Tarsier populations to donate 20 hectares (49 acres) of forestland for conservation.

It also runs a Tarsier Research and Development Center, which serves as a visitor center and venue for research, as well as a habitat preserve.[36] At the sanctuary, a spacious net enclosure keeps 100 Philippine Tarsiers for feeding, captive breeding and display. Here, visitors can observe the Philippine Tarsier in their natural habitat. Within the sanctuary, the Philippine Tarsiers roam freely and all of them have gotten used to a seven-foot high fence that circumscribes the territory and which serves mainly to protect them from predators like feral cats. At night, tarsiers can be seen climbing out of the fence to forage for food farther into the forest. They return again before daybreak, as if observing a curfew.[29]

Tarsier Sanctuary captive display

Captive tarsier display in Loboc, Bohol

Because the Philippine Tarsier sanctuary in Corella, Bohol is off the tourist path,[37] private individuals in Loboc, Bohol have provided an alternative way for tourists to see them through their displays of the Philippine Tarsier along the Loboc river banks. This captive tarsier display is conveniently on the way to other tourist spots in Bohol, particularly the Chocolate Hills in Carmen town.[38] Despite the protection status of the Philippine Tarsier, the Department of Environment and Natural Resources has granted special limited permits for this display of the Philippine Tarsier in Loboc. Here, tourists can see the Philippine Tarsier up close and personal and take pictures, but are not allowed to touch them. Unfortunately, the Philippine Tarsier here are semi-captive, being kept in cages along the Loboc river. Here, the animals are not in a sanctuary and as such, these shy animals have miserable lives and normally don't survive for long.[39] Though they are allowed to leave their cages at night to hunt for food, this is contrary to the ban on possession of Philippine Tarsier by virtue of its protected status. Proclamation 1030 states that "the possession of the Philippine Tarsier is only allowed for educational, scientific, conservation-centered research purposes upon certification of the Department of Environment and Natural Resources (DENR) Secretary." Further, the possession of these tarsiers for display encourages their possession as pets.[38]

Possession and display of tarsiers banned in Loboc

The Sangguniang Panlalawigan of Bohol passed Ordinance 015-2008 prohibiting the possession and display of tarsiers in the towns Loay and Loboc, Bohol.

In 2008, a tarsier in one of the caged tourist viewing sites in Loboc was found bleeding through its legs and clinging to a tree, lookeing stressed and lonely. The tarsier was found to have an infection that led to the bleeding[40]

Although it is rare to hear reports of injured tarsiers, provincial lawmakers are already pushing for an immediate regulation in issuing permits to private individuals and entities displaying tarsiers away from their natural habitat.

A report in GMA News’ “24 Oras” on February 18, 2009 said the approval of the measure was triggered by the proliferation of farms and businesses that are displaying tarsiers for a fee.[41]

Violators of the ordinance would be slapped with a P5,000 fine and will be meted with a jail term of not less than six months, the report said.

The report said tarsiers suffer stress every time they are exposed to humans. It added that the provincial government wanted tarsiers to remain in their natural habitat.

The provincial government also passed a resolution urging the Environment Department to stop issuing wildlife permits that allow the use of tarsiers for commercial purposes.[42]